textproduct: Rapid City

KEY MESSAGES

- Light rain and rain showers will increase across the region today, especially across South Dakota, becoming more widespread by Monday morning.

- A trace to an inch of snow is possible over northwestern South Dakota and the Black Hills on Monday.

- Warming trend commences Tuesday through the end of the week with highs in the 50s to 60s.

UPDATE

Issued at 952 PM MDT Sat Oct 24 2026

03z surface analysis had high from southwestern Canada into the Midwest. Water vapour loop had upper low over northern AZ. Some high clouds passing overhead with better moisture/lower clouds over NE starting to move toward the CWA. Upper low moves north/northeast through Monday. It will help easterly component to low level upslope flow on backside of surface high, bringing additional low level moisture into the CWA. Synoptic lift evidenced by modest 700-500mb QG-forcing blob that will move into the area by Sunday afternoon in earnest, exiting Monday afternoon. Best moisture transport east of the Black Hills, where highest QPF planted per 25th to 75th liquid equivalent percentiles. Upslope flow will support areas of lighter QPF over far western SD. Forecast soundings give rain through Sunday afternoon, but then weak dynamic cooling produces enough cold air for some snow over the higher elevations and over far northwestern SD. Ground temperatures and bulk of coldest air over the area Monday don't bode well for much sticking snow. Some pretty pictures of snow on grassy areas are sure to be seen. Secondary upper low wobbles across the northern Rockies into the northern Plains Tuesday, but low level flow becomes westerly/downslope, so moisture availability looks to be scant right now.

Themes of current forecast intact with some tweaks to timing/PoPs to account for latest ensemble guidance trends.

DISCUSSION

(This Evening Through Saturday) Issued at 1217 PM MDT Sat Oct 24 2026

Sfc analysis shows strong cold front has pushed to the east of the forecast area with northwest winds steadily diminishing through this morning. Upper level analysis and water vapor show a closed upper low over AZ with convection moving through northern NM. Meanwhile to the north of the Dakotas, an upper low spins over central SK. Expect clearing skies through this afternoon thanks to height rises and drier air moving into the area. Highs this afternoon will be more seasonable, ranging from the upper 40s to mid 50s.

Our next round of precip will move into the area Sunday afternoon as the upper low over the Desert Southwest begins to slowly move into the region. Area of modest QG forcing along with near saturated moisture profiles from around H850 to H700 will support precip in the form of rain beginning overnight tonight into early Sunday morning across south central SD and moving northward through the day as the upper low drifts northeast. Rain will continue through the overnight hours Sunday with the Black Hills getting cold enough for some snow to mix in.

The upper low continues its trek across the region through Monday with chances for precip continuing through the day. As colder air associated with the core of the upper low moves into the area, snow may begin to mix in with the rain, especially over northwestern SD and in and around the Black Hills. We may see a transition to all snow over the Black Hills and far northwestern SD late in the afternoon to evening. In terms of accumulations, there's still a little uncertainty as it will depend on when the colder air moves in at the mid levels and the exact track of the low. Even so, any accumulations are expected to be minor with some areas over the northwestern SD plains and Black Hills potentially seeing a dusting up to an inch of slushy accumulation. Any accumulations should be gone by Tuesday as warmer air moves back into the region.

Upper level shortwave and attendant moisture starved front will move in from the PNW later on Tuesday. Could see some light rain showers across far northeastern WY into northwestern SD with this system with the only other impacts expected being breezy southwest winds across the western SD plains and portions of northeastern WY late Tuesday afternoon. Otherwise, upper level west- southwesterly flow will keep temperatures seasonably mild after Tuesday with dry weather expected through the late week.

AVIATION

(For the 12Z TAFS Through 12Z Monday Morning) Issued At 544 AM MDT Sun Oct 25 2026

We open the morning with dry VFR conditions across most of the region, but lower cloud decks are on our doorstep starting to move into the southern tier counties of South Dakota from the south. Cigs will trend into MVFR today at KRAP and into IFR by tonight, while it may take until tonight before cigs approach MVFR as far west as KGCC. Potential and coverage of light rain showers will also gradually increase today over South Dakota, especially east of the Black Hills, and while some guidance brings showers close to KRAP as early as midday, have continued to focus the ongoing PROB30 on tonight when better consensus in nearby showers exists. Even lower clouds, increasing BR/lower vsbys, and increasing coverage of rain (mixed with snow in some spots) is likely by Monday morning near or just beyond the end of the current TAF period, again especially over South Dakota including KRAP.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.